CN105016317A - Cubic boron nitride monocrystal purification method - Google Patents

Abstract

The invention provides a cubic boron nitride monocrystal purification method. The method comprises the steps of firstly, preparing ammonium base salts according to the ratio, wherein water, ammonium bifluoride and an ammonium salt addition agent are taken on the basis that the ratio of the water to the ammonium bifluoride to the ammonium salt addition agent is 1:6-10:0.5-3; secondly, performing reactive separation, wherein the obtained ammonium base salt mixing solution is poured into a reaction kettle, and the mixing solution is added into a cubic boron nitride concentrate obtained through a conventional tabling method on the basis that the ratio of the cubic boron nitride concentrate to the mixing solution is 1:1-2, and then heating is performed for a reaction for 60-120 min at the temperature being 130-150 DEG C; thirdly, performing filtering and cleaning, wherein tap water is used for filtering out feed liquid obtained from the reaction in the second step, and the obtained cubic boron nitride obtained after filtering is performed is cleaned thoroughly through the clean water and then placed into a drying oven to be dried. According to the cubic boron nitride monocrystal purification method, the production technology is simplified, the cost is lowered, the industrial continuous operation is facilitated, emission is controllable, no harm is caused to the human body, and it is ensured that boron nitride and other impurities in the cubic boron nitride monocrystals are removed.

Description

Cubic boron nitride monocrystal method of purification

Technical field

The invention belongs to superhard material synthesis technical field, be specifically related to a kind of cubic boron nitride monocrystal method of purification.

Background technology

In known technology, existing cubic boron nitride (CBN) normally adopt hexagonal boron nitride (hBN) for raw material catalyst participate under through High Temperature High Pressure process synthesis, in the product of synthesis except CBN, also has unconverted hBN, catalyzer, graphite, the material such as rhombspar and agalmatolite, synthetic rod is soaked and selects cubic boron nitride fine fodder by tabling, CBN content about 95 ~ 98% in CBN fine fodder, still have residual hBN and agalmatolite, usual employing high-temperature alkali treatment process is purified, namely mix with 2 ~ 4:1 weight ratio with highly basic sodium hydroxide/potassium hydroxide and CBN fine fodder, be warmed to 300 ~ 350 DEG C, 3 ~ 4h reacts dissolving and removes hBN and agalmatolite, then pure CBN crystal is obtained after rinsing with diluted acid neutralization and water.

This method of purification major defect is:

1) need to carry out pyroprocessing with a large amount of sodium hydroxide/potassium hydroxide highly basic, need a large amount of diluted acid neutralizations, resource consumption is large, and production cost is high;

2) boil in alkali process after alkali lye thawing, the alkali lye evaporated easily splashes on operator's skin, easily causes operator's health to corrode injury, is detrimental to health;

3) the purification process time is long, and every pot for the treatment of capacity is little, is no more than 6Kg, needs a large amount of manpower and strong physical work, and is not suitable for industrialization and works continuously, and time-consuming, purification production efficiency is low.

Summary of the invention

The object of this invention is to provide a kind of new treatment process to replace high-temperature alkali, and provide a kind of simplification production technique, reduce costs, be convenient to industrialization and work continuously, controlled discharge, do not injure human body, can ensure again to remove hexagonal boron nitride and other impurity in cubic boron nitride monocrystal.

The technical solution used in the present invention is: a kind of cubic boron nitride monocrystal method of purification, comprises the following steps:

The first step, prepares ammonium system salt proportioning: water intaking, ammonium bifluoride and ammonium salt auxiliary agent respectively, and according to water: ammonium bifluoride: proportioning is carried out in ammonium salt auxiliary agent=1:6 ~ 10:0.5 ~ 3;

Second step, Reaction Separation: the ammonium system salt mixed solution getting preparation injects in reactor, by cubic boron nitride fine fodder: the weight proportion of mixed solution=1:1 ~ 2 adds the cubic boron nitride fine fodder after conventional tabling process, then heat, under 130 ~ 150 DEG C of temperature condition, react 60 ~ 120min;

3rd step, filters cleaning: reacted for second step feed liquid leached with tap water, rinsed well by the cubic boron nitride clear water leached, put into oven for drying.

Further, described ammonium salt auxiliary agent is ammonium fluoride, ammonium chloride, ammonium sulfate or ammonium nitrate.

Method for purifying cubic boron nitride of the present invention, the mixed solution of ammonium bifluoride, ammonium salt auxiliary agent and water is utilized to react with hexagonal boron nitride and agalmatolite at lower than the temperature of 150 DEG C, decrease the usage quantity of pharmaceutical chemicals, reaction process temperature is lower, can mass disposal in a kettle.; Discharge controlled, thus can not produce toxic gas, thus avoid topsoil in purification process, after reaction terminates, purely can not occur at a large amount of alkaline liquids, to be finally discharged in waste water acid content little, correspondingly decrease intractability.

The method of purification of synthesizing cubic boron nitride of the present invention is compared with traditional treatment method, removing hexagonal boron nitride that can not only be clean, can not cause any harm to human body simultaneously, moreover operation is simple, purification efficiency is high, is convenient to large-scale industrial production, and the liquid of generation is convenient to process, can not work the mischief to environment such as air, water, soil, thus greatly reduce production cost.

Embodiment

Be the first embodiment of the present invention below:

First fetch water 2 Kg, ammonium bifluoride 20Kg, ammonium sulfate 6Kg, inject container to stir, make mixing solutions, again the mixing solutions of preparation is injected in reactor, getting cubic boron nitride content is in the fine fodder 18 Kg input reactor of 95%, then 140 DEG C are heated to, insulation 1.5h, reaction stops, add tap water in a kettle., by the punching of the mixture of the inside to in container, the cubic boron nitride clear water leached is rinsed well, puts into oven for drying and can obtain pure cubic boron nitride.Do not find impurity through microscopy, plane of crystal is glittering.

Be the second embodiment of the present invention below:

First fetch water 3 Kg, ammonium bifluoride 24 Kg, Neutral ammonium fluoride 8 Kg, inject container to stir, make mixing solutions, again the mixing solutions of preparation is injected in reactor, getting cubic boron nitride content is in the fine fodder 20 Kg input reactor of 97%, then 150 DEG C are heated to, insulation 2h, reaction stops, add tap water in a kettle., by the punching of the mixture of the inside to in container, the cubic boron nitride clear water leached is rinsed well, puts into oven for drying and can obtain pure cubic boron nitride.Do not find impurity through microscopy, plane of crystal is glittering.

Be the third embodiment of the present invention below:

First fetch water 4.2 Kg, ammonium bifluoride 34 Kg, ammonium chloride 4.2Kg, inject container to stir, make mixing solutions, then the mixing solutions of preparation is injected in reactor, get fine fodder 24 Kg that cubic boron nitride content is 96%, then be heated to 150 DEG C, insulation 1.5h, reaction stops, add tap water in a kettle., by the punching of the mixture of the inside to in container, the cubic boron nitride clear water leached is rinsed well, puts into oven for drying and can obtain pure cubic boron nitride.Do not find impurity through microscopy, plane of crystal is glittering.

Claims (2)

1. a cubic boron nitride monocrystal method of purification, is characterized in that: comprise the following steps:

The first step, prepares ammonium system salt proportioning: water intaking, ammonium bifluoride and ammonium salt auxiliary agent respectively, and according to water: ammonium bifluoride: proportioning is carried out in ammonium salt auxiliary agent=1:6 ~ 10:0.5 ~ 3;

Second step, Reaction Separation: the ammonium system salt mixed solution getting preparation injects in reactor, by cubic boron nitride fine fodder: the weight proportion of mixed solution=1:1 ~ 2 adds the cubic boron nitride fine fodder after conventional tabling process, then heat, under 130 ~ 150 DEG C of temperature condition, react 60 ~ 120min;

3rd step, filters cleaning: reacted for second step feed liquid leached with tap water, rinsed well by the cubic boron nitride clear water leached, put into oven for drying.

2. a kind of cubic boron nitride monocrystal method of purification according to claim 1, is characterized in that: described ammonium salt auxiliary agent is ammonium fluoride, ammonium chloride, ammonium sulfate or ammonium nitrate.